Dynamics-based control of a one-legged hopping robot

2003 ◽  
Vol 217 (2) ◽  
pp. 83-98 ◽  
Author(s):  
S H Hyon ◽  
T Emura ◽  
T Mita
Keyword(s):  
Complex Analysis ◽  
Dynamics Model ◽  
Linear Complex ◽  
Actuator Dynamics ◽  
New Model ◽  
Rapid Movement ◽  
Hopping Robot ◽  
Non Linear ◽  
The One

This paper proposes a new model of a one-legged hopping robot. The one-legged hopping robot is useful in realizing rapid movement such as that of a running animal. Although it has a simple leg mechanism, the dynamics are not simple and require non-linear complex analysis. This means that it is not easy to derive a controller for stable hopping in a systematic way. Therefore, a dynamics-based approach was introduced where the controller is empirically derived based on characteristic dynamics. A prototype of the one-legged hopping robot was fabricated and a precise simulator of the robot, including actuator dynamics, was constructed to examine the usefulness of the proposed dynamics model. Applying the constructed simulator to the prototype, the robot succeeded in planar one-legged hopping.

Getting Over Athens

2018 ◽  
Author(s):  
Nicolas Wiater
Keyword(s):  
Roman Empire ◽  
The Other ◽  
The Political ◽  
New Model ◽  
Dionysius Of Halicarnassus ◽  
The One

This chapter examines the ambivalent image of Classical Athens in Dionysius of Halicarnassus’ Roman Antiquities. This image reflects a deep-seated ambiguity of Dionysius’ Classicist ideology: on the one hand, there is no question for Dionysius that Athenocentric Hellenicity failed, and that the Roman empire has superseded Athens’ role once and for all as the political and cultural centre of the oikoumene. On the other, Dionysius accepted Rome’s supremacy as legitimate partly because he believed (and wanted his readers to believe) her to be the legitimate heir of Classical Athens and Classical Athenian civic ideology. As a result, Dionysius develops a new model of Hellenicity for Roman Greeks loyal to the new political and cultural centre of Rome. This new model of Greek identity incorporates and builds on Classical Athenian ideals, institutions, and culture, but also supersedes them.

Models of a hybrid wheeled hopping self-balanced robot

2021 ◽  
pp. 095440622098419
Author(s):  
Qimin Li ◽  
Haibing Zeng ◽  
Long Bai ◽  
Zijian An
Keyword(s):  
Pid Control ◽  
Motion Pattern ◽  
System Dynamics Model ◽  
Dynamics Model ◽  
Swarm Optimization ◽  
Hopping Robot ◽  
Control Scheme ◽  
Hopping Robots ◽  
Hybrid Motion ◽  
Classical Control

Combining wheeled structure with hopping mechanism, this paper purposes a self-balanced hopping robot with hybrid motion pattern. The main actuator which is the cylindrical cam, optimized by particle swarm optimization (PSO), is equipped with the motor to control the hopping motion. Robotic system dynamics model is established and solved by Lagrangian method. After linearization, control characteristics of the system is obtained by classical control theory based on dynamics equations. By applying Adams and Matlab to simulate the system, hopping locomotion and self-balanced capability are validated respectively, and result shows that jump height can reach 750 mm theoretically. Then PID control scheme is developed and specific models of hardware and software are settled down accordingly. Finally, prototype is implemented and series of hopping experiments are conducted, showing that with different projectile angle, prototype can jump 550 mm in height and 460 mm in length, transcending majority of other existing hopping robots.

Cycles in symbol production? A new model to explain concentration, diversity and innovation in the music industry

Popular Music ◽  
1995 ◽  
Vol 14 (1) ◽  
pp. 55-93 ◽  
Author(s):  
Michael Christianen
Keyword(s):  
Negative Correlation ◽  
Music Industry ◽  
The Other ◽  
Recording Industry ◽  
Cultural Goods ◽  
New Model ◽  
Advantages And Disadvantages ◽  
Factors Influencing ◽  
Using Data ◽  
The One

With the publication of the article ‘Cycles in symbol production’ (Peterson and Berger 1975) a discussion started concerning the advantages and disadvantages of the production of cultural goods under market conditions. The analysis by Peterson and Berger showed a negative correlation between concentration in the recording industry, on the one hand, and the diversity and innovativeness of the music, on the other. Repetition of the analysis using data from the 1980s (Burnett 1990; Lopes 1992) has shown that for this period Peterson and Berger's hypotheses should be rejected. Is there a connection between concentration and diversity and innovation? Are there cycles in symbol production? There seems to be no conclusive answer. In this article, I will attempt to clear up this matter. First, I will repeat the analysis of the relation between concentration and diversity/innovation, using the same model as Peterson and Berger, but with different definitions for the variables concentration, diversity and innovation. Then I will suggest a new model, which can be helpful in uncovering other factors influencing diversity and innovation in the music industry. I will come to that later. Let me first give the reader a brief overview of previous research.

scholarly journals A New Model Approach for Convective Wall Heat Losses in DQMOM-IEM Simulations for Turbulent Reactive Flows

2018 ◽  
Vol 141 (5) ◽  
Author(s):  
Yeshaswini Emmi ◽  
Andreas Fiolitakis ◽  
Manfred Aigner ◽  
Franklin Genin ◽  
Khawar Syed
Keyword(s):  
Experimental Data ◽  
Heat Losses ◽  
Reacting Flow ◽  
Jet Flame ◽  
New Model ◽  
Turbulent Reactive Flows ◽  
Novel Method ◽  
The One ◽  
The Impact ◽  
Model Approach

A new model approach is presented in this work for including convective wall heat losses in the direct quadrature method of moments (DQMoM) approach, which is used here to solve the transport equation of the one-point, one-time joint thermochemical probability density function (PDF). This is of particular interest in the context of designing industrial combustors, where wall heat losses play a crucial role. In the present work, the novel method is derived for the first time and validated against experimental data for the thermal entrance region of a pipe. The impact of varying model-specific boundary conditions is analyzed. It is then used to simulate the turbulent reacting flow of a confined methane jet flame. The simulations are carried out using the DLR in-house computational fluid dynamics code THETA. It is found that the DQMoM approach presented here agrees well with the experimental data and ratifies the use of the new convective wall heat losses model.

Non-linear dynamic modelling of a switching valve driven by pulse width modulation in the hydraulic braking system of a vehicle

2016 ◽  
Vol 231 (11) ◽  
pp. 1511-1529
Author(s):  
Xiang Gao ◽  
Yiyong Yang ◽  
Xun Zhao ◽  
Chenfeng Li
Keyword(s):  
Fluid Dynamics ◽  
Dynamic Modelling ◽  
Stability Control ◽  
Dynamics Model ◽  
Predictive Tool ◽  
Element Analysis ◽  
Linear Dynamics ◽  
Switching Valve ◽  
Fast Switching ◽  
Non Linear

Fast-switching valves driven by puse width modulation have been widely used in the hydraulic braking systems (such as anti-lock braking systems or electric stability control systems) of vehicles, because of their lower cost and their functions which are similar to those of proportional valves. However, proportional valves have been widely investigated, whereas there is significantly less literature on the switching valves of the hydraulic control units in the braking systems of vehicles. In order to investigate the controllability of pressure, construction of an accurate theoretical model is the key to attaining this. Based on theoretical analysis and finite element analysis, this paper presents a non-linear dynamics model of a typical fast-switching valve. The non-linear model is composed of three submodels: a mechanical submodel, an electromagnetic submodel and a fluid dynamics submodel. The fluid momentum theorem combined with the simulation curve-fitting method is used to model accurately the fluid dynamics which are due to the varying flow field. The hydraulic force acting on the spool can be obtained directly from this model. Finally, the feasibility of the response time and the pressurization performance of the non-linear dynamics model is proved by comparing the simulation results from MATLAB/Simulink with the experimental results obtained on a test bench. The study shows that the model can be regarded as a predictive tool for future investigation.

DROPLET FEEDBACK ON VAPOR IN A WARM CLOUD

2009 ◽  
Vol 23 (28n29) ◽  
pp. 5434-5443 ◽  
Author(s):  
ANTONIO CELANI ◽  
ANDREA MAZZINO ◽  
MARCO TIZZI
Keyword(s):  
Numerical Simulations ◽  
Droplet Size ◽  
Cloud Droplet ◽  
Direct Numerical Simulations ◽  
Cloud Droplets ◽  
Size Spectra ◽  
New Model ◽  
Warm Cloud ◽  
Local Reduction ◽  
The One

A new model to study the effect of turbulence on the cloud droplets in the condensation phase is proposed and its behavior investigated by direct numerical simulations. The model is a generalization of the one by Celani, Mazzino, Tizzi, New J. Phys.10, 075021 (2008), where the droplet feedback on vapor is now explicitly taken into account. Physically, it amounts to considering the fact that when a cloud droplet increases its size, vapor is subtracted from the ambient with the net result of a local reduction in the supersaturation field. It is shown how this effect plays to reduce the broadening of droplet size spectra in the condensation stage and thus to produce results in closer agreement with observations.

Black British drama, losses and gains: the case of Shoot the Messenger

2017 ◽  
Author(s):  
Sarita Malik
Keyword(s):  
Black Women ◽  
Linear Form ◽  
Black Male ◽  
Social Realism ◽  
Television Drama ◽  
Black Representation ◽  
Black British ◽  
British Drama ◽  
Non Linear ◽  
The One

This chapter contributes to the debates around television drama and black representation that are presented in this book collection. It focuses on Shoot the Messenger (STM) (BBC2, 2006), which was heavily promoted by the BBC as a ‘bold’ and ‘thought-provoking’ television drama. The one-off ninety-minute BBC Drama production focuses on the psychological journey of a Black schoolteacher, Joe Pascale (portrayed by David Oyelowo), accused of assaulting a Black male pupil. This chapter discusses how stylistically, STM’s non-realist techniques, non-linear form and overt constructedness depart from the traditional modes of social realism that have prevailed in Black British television drama. Moreover, it breaks with British television drama traditions in terms of production, having an almost totally Black cast and written and produced by two Black women: Sharon Foster and Ngozi Onwurah respectively.

Changing shape according to strength: Evidence from root allomorphy in Greek

2019 ◽  
Vol 36 (3) ◽  
pp. 553-574 ◽  
Author(s):  
Anthi Revithiadou ◽  
Giorgos Markopoulos ◽  
Vassilios Spyropoulos
Keyword(s):  
The Other ◽  
Activation Level ◽  
Vocabulary Item ◽  
Non Linear ◽  
The One ◽  
Surface Realization

Abstract In this article we examine patterns of root allomorphy in Greek that involve vowel alternations and propose a Generalized Non-linear Affixation (Bermúdez-Otero 2012) analysis according to which these alternations result from the competition between segments that belong, on the one hand, to the vocabulary items of roots and, on the other, to the exponents of functional heads (Voice/Aspect, n). More specifically, we claim that phonological entities have a gradient degree of presence in a structure, that is, are specified with a certain activation strength value underlyingly (Smolensky and Goldrick 2016). As a result, the surface realization of roots is determined by the relevant activation level of the exponents of functional heads they are eventually combined with. From all available exponents, the one that optimally complements the strength value of the vocabulary item of a given root will eventually surface. Our analysis is shown to be theoretically advantageous because it develops a strictly phonological account of allomorphy and, moreover, it captures the attested generalizations without resorting to extensive stem/span listing or to the application of phonologically unrestricted readjustment rules.

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